Timber elements may be joined together by a skew nail penetrating the members to be joined, by plate or gang nail connectors, or by bent nail arrangements. For timber trusses, gang nails predominate as the connector of choice. For joining one timber element at right angles to another, such as studs to top and bottom plates of wall frames, skewed nails are often used. A stronger joint may be effected by using a bent nail I developed, and which is disclosed in Australian Patent No. 628834. However, there are shortcomings in these earlier connectors. One such shortcoming is that when not being used, such nails create a safety problem is left on the ground or floor because their natural orientation leaves a spike projecting in a substantially upward direction.
Although skew nails are very quick to insert, the strength of the joint is dependant, to a considerable extent, on the skill of the person making the joint. Moreover, skew-nailed joints do not provide a high resistance to separation of the joined elements because the nails themselves do not have a high resistance to withdrawal from the timber elements, even when such nails are inserted at an optimum angle or with optimum effect.
Gang nail plates usually provide a stronger joint than straight or skewed nail joints, but still do not provide a high resistance to separation of the joined elements. Additionally, gang nails are difficult to install by hand, being prone to bending of the plate or flattening of one or more of the pins or spikes unless installed by a hydraulic press or the like.
The bent nail disclosed in Australian Patent No. 628834 provides a superior strength joint. Refinements to that nail have been shown to provide excellent joint strength for cyclone applications. However, that nail is difficult to install by hand and requires a specially developed nail gun to be installed automatically.
After seeking to refine the nail disclosed in my earlier patent application, it has been surprisingly found that a new range of parameters provides superior results to all of the abovementioned connectors. Since the filing of my Australian Provisional Patent Application No. 2003904358, it has been discovered that without careful selection of appropriate parameters for such nails, the timber joints cannot flex to an optimum amount, affording such joints greater efficacy and less tendency to failure in temporary high load situations such as subjecting structures to cyclonic wind storms. Additionally, in prior art nails, timber can sometime be more prone to splitting.
The present invention aims to provide connectors for timber which are an improvement, on the timber connectors of the prior art. It is also an aim of the invention to provide improved timber connectors which alleviate one or more of the disadvantages of prior art connectors. Other aims and advantages of the invention may become apparent from the following description.